Process of cracking hydrocarbons



Feb. 7, 1933. EGLOFF PROCESS OF CRACKING HYDROCARBONS Filed Dec. 21 1925wag/.1:

Patented Feb. 7, 1933 u rrED STATES.

PATENT orrlcs GUSTAV nenorr, or CHICAGO, ILLINOIS, ASSIGNOR, T UNivERsALOIL rnonuc'rs COMPANY, OF CHICAGO, ILLINOIS,'A CORPORATION OF SOUTHDAKOTA rnocnss or cnacxme n nnocaanoivs' Application filed December 21,1925. Serial No. 76,636.

This invention relates to improvements in process of crackinghydrocarbons, and in general refers to a process in which the oil afterhaving been subjected to crackingconditions of temperature and pressureso as to substantially vaporize the oil, the vapors are furthersuperheated under cracking conditions of pressure to produceasubstantial yield of aromatic hydrocarbons therefrom, and so calledfixed. gases high in-their content of v boiling point aromatichydrocarbons.

.Aromatics of the above character are now commercially produced. verylargely from the distillation of coal, but'it is the essence of thepresent invention to produce them from the cracking of petroleum oil, ina more practical and efiicient manner than heretofore attempted.

In order to more clearly understand the invention, I have shown theaccompanying drawing, which is a more orless diagram.- matic sideelevational view of an apparatus in which the invention may be carriedout.

Referring to the drawing, 1 designates a furnace in which is mounted theheating tube 2 connected at its inlet side to the raw oil pump 3,and.atits outlet side through the transfer line 4 having throttle valve 5 toan enlarged expansion tank or chamber 6. This tank or chamber may beprovided with a residuum drawolf 7 controlled by throttle valve 8 andwith vapor-outlet line 9. con-' trolled by throttle valve 10. Thevaporpipe 9 is in turn connected to a second heating tube 12 located inthe furnace 13. The delivery end of this coil is connected throughtransfer line 14 to a second expansion chamber 15 which may, if desired,e mounted in a suitable setting 16. The chamber 15 may be provided withresiduum drawofi 17 controlled by throttlevalve 18 and with vapor pipe19 having throttle valve 20 leading into the lower end of thedepblegmator 21. The arrangement is such that vapors can pass into thedepblegmator, but the reflux condensate cannot fall down throughthe pipe19 into the chamber 15. The depblegmator may be provided with aplurality of baflles 22 and vapor outlet pipe 23 having throttle valve24, which pipe 23 leads to the WatercOndenser 2'5 and thence to receiver26 between which is interposed. throttle valve 27. The receiver 26 is"equipped with gas outlet pipe 28 controlled by throttle valve 29.The'pipe 28 may be connected with suitable gas holder not shown. Thereceiver 26 is also equipped with liquid drawofi pipe 30 controlled bythrottle-valve 31.

The reflux condensate from the lower portion of the dephlegmator 21 isdrawn oif .through the pipe 32 in which is preferably interposed a pump33 having at either side thereof throttle valves 34 and 35. The reflux Icondensate may be pumped from line 32 through the extension 36 to thevapor pipe 9, or by closing the throttle valve 31 and openin thethrottle valve 38 in the branch 40 the re ux condensate may be deliveredto storage or elsewhere, as desired. However, in carrying out myinvention, I find it will be advantageous in some cases at least, toreturn the reflux condensate to the line 9 where it is-mixed with thevaporsv in said line.

he raw oil in a preheated condition, may be fed from storage tank '41 bymeans of pump 42 and pipe 43 to the closed coil 44 seated in thedepblegmator, and thence through pipe 45 to the raw oil pump 3. Ifdesired, the oil may be partially or wholly by-passed through the line46 and throttle valve 47 In the event the line 46 is used, the valve 48in the line 45 may be wholly or partially closed. A check valve 49 :isinterposed in the line 36, andso positioned that it only sulated, or maybe externally and independently heated, the tank 6 being heated througha suitable furnace, not shown, if such heating is there desired.

One method of carrying out the invention may be described as follows:

Gas oil of 32 Baum gravity from the Kansas field, may be fed through theheating coil 2 where it is heated to a transfer temperature of say 900F. while under say 1000 pounds more or less pressure. more or lessliquid-vaporphase is passed to 'the expansion chamber 6, where it may bemaintained at say 400 pounds pressure, more or less, the vapors leavingthe expansion chamber at say 875 F. The vapors pass from the line 9 intothe heating coil 12 where they may be heated to a vapor temperature ofsay 1200 F. while subjected to a pressure of 200 pounds. If the refluxis mixed with the vapors before entering the coil 12, the reflux willlikewise be vaporized and heated to such temperature at such pressure.The superheated vapors then pass through line 14 into the expansionchamber 15 where the ressure may bev at 150 pounds through suitablycontrolled reducing valve 14 The vapors pass out through the vaporoutlet 19 into the dephlegmator 21 where the heavier portions thereofare condensed and drawn out of the dephlegmator and either sent tostorage as for example, the storage tank 41 or they may be mixedwith thevapors in the ipe 9. If desired, only a portion of the re ux condensateis passed to the pipe 9 while the other portion is drawn off elsewhere.This will permit V of controlling the relative proportion of reflux tothe vapors in the pipe 9. The temperature of the dephlegmator may be socontrolled either by the closed coil 44 herein described, or in anyother suitable manner now well known in the art, so that they will leavethe top of the dephlegmator at say 400 F., and thence pass into thewater condenser 25 and thence to the receiver 26. By suitablycontrolling the valve 24, a pressure of say 125 pounds may bemaintained-on the dephlegmator, and by controlling the valve 27, apressure of 100 pounds may be maintained on the water condenser; bysuitably controlling the valve in the receiver, a pressure of say poundsmay be maintained on the receiver.

It is understood that it may be desirable in one method of operating theapparatus here shown, to accomplish certain desired results, to have theentire system under the same pressure of say 200 pounds more or less.

The oil in a for use in the so-called anti-knock motor fuels. It is wellknown to those skilled in the art that aromatic hydrocarbons are betteranti-knock motor fuels than paraffine hydrocarbons. Furthermore, bymeans of this process not only is a high percentage of aromatichydrocarbons formed, but also a much larger percentage of olefines andalso diolefines. It is also well known, that these olefine hydrocarbonsare highly desirable as anti-knock motor fuels.

I claim as my invention:

1. A continuous process for cracking hydrocarbons, comprising initiallyraising a hydrocarbon oil to a cracking temperature while under asuperatmospheric pressure, removing from the hydrocarbon oil such vaporsas are evolved therefrom, raising the temperature of all of such vapors,prior to condensation, substantially 300 F., above the temperature towhich said hydrocarbon oil was initiallysubjected, thereafter subjectingsuch va orsto reflux condensation and uniting re ux condensate separatedfrom the vapors with the vaporo'us constituents being evolved from saidhydrocarbon oil without returning said reflux condensate to the oil fromwhich the vapors are evolved.

2. A process for cracking hydrocarbon oil, comprising initially heatingthe oil to a cracking temperature under superatmospheric pressure,thereafter permitting the oil to By carrying out the invention in themanner hereinbefore described, I convert a substantial part of theoriginal charging stock

